This technical note describes the recommended settings for integrating AB devices on a Data Highway network using the AB-1756 DHRIO gateway and embedded DF1 messages from the Generic Device Ethernet/IP driver for the Virtual IO module.
The Allen Bradley Data Highway Plus Remote I/O Communications Interface (DHRIO module) is a gateway used to interface the Logix 5000 series controllers to the AB PLCs (PLC5, and SLC) via DH+. This gateway can translate Ethernet/IP embedded DF1 messages to DH+ format, send the message to the remote PLC and translate and return the response. In order to use this gateway from DeltaV, the Generic Ethernet/IP firmware (4.1.x or greater) must be flashed to the VIM. Each DF1 message is defined in the VimNet Explorer Ethernet/IP Connection Library.
This section provides information for configuring the 1756-DHRIO connection to the VIM. It assumes the user is familiar with the configuring the VIM using the VimNet Explorer Utility. This device requires Class3 connections with embedded DF1 messages.
Open VimNet Explorer. Right-click on the “EthernetIP Connection Library” leaf in the navigational panel on the left of the display. Select “Add Connection Definition” (Figure 1).
The “Add Connection Definition” (Figure 2) will automatically open the connection definition edit dialog. This opens the “VIM_EtipBufferMapping." This is the utility that allows the configuration of the connection between the VIM and the 1756-DHRIO module.
The connection definition dialog is comprised of several areas. The upper left corner has the Library Name and Version. These are used to uniquely identify a connection definition. Below this is the Ethernet/IP buffer definition. This includes the radio buttons to specify the message type (must be class3 for this device), and the message buffer sizes. Below this are the base dataset definition (one dataset is required for each DF1 message).
The three grids on the right are not used for mapping of DF1 data, the data from PLC files is right side of the dialog has three grids; the top allows the mapping of the input buffer into the specified datasets, while the middle grid allows the mapping of the output buffer. The bottom grid is not necessary for this application.
You enter a new name in the “Library Name” field. This is the name that will be displayed in the VinNet Explorer library. The name must be unique to the library for each connection definition. If no name is entered, a default name is created that describes the definition (i.e., C3DF1_Typed_N:7/0-99 for a Class3 (C3), DF1 message (DF1) using the PLC5 typed format (Typed) for an integer (N) file, registers 0 to 99).
Make sure the message type radio button (Class3) is checked and the DF1 field is checked (Class3 embedded DF1 message), and select the “MsgParameters” button to open the “DF1 Message Parameters dialog.”
This dialog allows you to enter or modify the necessary parameters to configure the actual Ethernet/IP Class3 connection. For the DHRIO, you should select a Service type of DHRIO "A" or DHRIO "B" depending on the port on the DHRIO module you are using to access the DH+ network.
Select the processor type of the remote PLC, the access message and file types and use access (available message and file types will vary depending on the Processor type selected). Then select the file number, offset word in the file to start access from and number of registers.
If the DHRIO module sits in a slot in the same rack as the ENBT card you will use for the connection, then enter the slot here (the ENBT port that access the rack backplane to access the slot is always 1), otherwise you may use the "Device Extended Address" in the Device properties dialog to assign the CIP path to the DHRIO module.
The update period must be specified here. This is the interval period between reads messages are sent to the PLC (writes are by exception from DeltaV). This read update period may be adjusted depending on the number of messages configured on the VIM and messages directed to the DHRIO module. The default is 500, if a message must be read faster set a lower number, 0 means the read message will be sent as fast as possible by the VIM. The actual update interval may be dependent on the response time from the remote PLC, and the number of connections on the VIM. This value may be viewed in VimNet Diagnostics. Setting the value to too low a number may actually slow the processing of messages, or may flood the DH+ network.
Each connection definition is added to a device. The device represents the remote PLC as well as the ENBT card used in the connection. To configure a device, select the Node, the specific VIM, card, and port. Right-click on this branch with the mouse and select “Add Device," to open the device properties dialog box. Select the device number (the device address that will be used for the device in the DeltaV IO tree definition). This address must match that in the DeltaV IO tree or results will be unpredictable, the data for the connection will not be returned, or will be incorrect.
Now either select the IP address from the list box of defined IP addresses (ENBT cards), or select the “Add” button to enter the IP address of the ENBT card that will be used for the connections. If “Add” is selected, the IP definition dialog is opened with a default IP address on the VIM subnet, and the default number of simultaneous messages (Class3 connection instances in this case). Increasing the number of Class3 connections will allow different messages to be sent at different update rates and may be used to improve the through-put of DF1 messages to the remote PLC(s). Once the IP address has been entered, select "OK" to return the the device properties dialog.
This device properties dialog also allows addition of an extended address to the Ethernet/IP connection if necessary. This CIP path is a text base address with one or more routing directions, each in the format of port, address.
For remote DH+ addressing select the DF1 extended address checkbox. Once checked the available addressing for the DH+ message are displayed. Set the “Dest Node” address to the Node ID of the remote PLC that is to be accessed. The remaining ID’s should be left as 0.
If multiple message types have been defined in the library, you may select those that are not supported by this device here. The excluded message types are not displayed in the selection combo box for adding connections; this will simplify the selection of definitions for connections. Each device may have a different exclusion pattern.
To add this Class3 connection to the VIM configuration, select the Node, the specific VIM, card, port and device for the connection, then right click on the device and select “Add Connection."
In the dialog box, add a description and select the specific connection definition from the “Ethernet Device Definition” combo box. The connection is added to the list and the next available dataset(s)in DeltaV are assigned.
The Slot number is editable here if the definition has the slot marked as “default." If more than one simultaneous messages were enable for the device the “Connection” number is the Class3 connection instance to assign this message to. The default is 1, but setting messages to the same DHRIO port to use different Class3 connections will improve message throughput. Each separate Class3 connection will use a connection in the DHRIO module and in the VIM. Multiple messages may be assigned to each Class3 connection instance.
You can examine the library definition by selecting the connection under the device in the IO tree. This is an abbreviated definition, for the complete definition, right-click on this item and select “Properties," then the “Edit” button. This opens the complete library definition for examination or editing.
You can display this connection by selecting the plus (+) in front of it, and examine the definition of the assigned dataset here. When configuring the actual DeltaV datasets (DeltaV Explorer), you may use these definitions as a reference.
The top section of the detail panel show the configuration required for the specified DeltaV dataset separated by tab (i.e., General Tab, DeltaV tag, etc.). The bottom section (Variable, DeltaV Path, Direction) is used for mapped datasets, not DF1 messaging.
DF1 message sent to a 1756-DHRIO module. This message is sent to the module via an explicit(Logix uses Class3), Service is specified as (0), Class, member, and attribute parameters are invalid.
The Connection object may be edited if required. The default values are set when the calling Service is changed (i.e., changed from DHRIO ‘A’ to DHRIO ‘B’) see figure Figure 11. These values are expected to be correct for the DHRIO module, but if required the values may be edited by selecting the “Advanced” button. This opens the “Class3 Connection Object” dialog.
The default values displayed are when the dialog is first opened (and following any change to the “Service” parameter in the “DF1 (Class3) Message Parameters” dialog.
Using RSLinx, select the DHRIO module in the IO tree, then select “Module Configuration” from the right button context menu.
The general configuration properties are displayed:
Select the Routing Table tab:
From this select the context menu item “Edit” to open the Module configuration, set the slot number and Channel Link IDs as required then select "OK," and "Apply."
At this time, you have completed the integrating AB devices on a Data Highway network using the AB-1756 DHRIO gateway and embedded DF1 messages from the Generic Device Ethernet/IP driver for the Virtual IO module.
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